drivers/i2c/busses/i2c-imx.c

   1 /*
   2  *      Copyright (C) 2002 Motorola GSG-China
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version 2
   7  *      of the License, or (at your option) any later version.
   8  *
   9  *      This program is distributed in the hope that it will be useful,
  10  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *      GNU General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License
  15  *      along with this program; if not, write to the Free Software
  16  *      Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
  17  *      USA.
  18  *
  19  * Author:
  20  *      Darius Augulis, Teltonika Inc.
  21  *
  22  * Desc.:
  23  *      Implementation of I2C Adapter/Algorithm Driver
  24  *      for I2C Bus integrated in Freescale i.MX/MXC processors
  25  *
  26  *      Derived from Motorola GSG China I2C example driver
  27  *
  28  *      Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de
  29  *      Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de
  30  *      Copyright (C) 2007 RightHand Technologies, Inc.
  31  *      Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
  32  *
  33  */
  34
  35 /** Includes *******************************************************************
  36 *******************************************************************************/
  37
  38 #include <linux/init.h>
  39 #include <linux/kernel.h>
  40 #include <linux/module.h>
  41 #include <linux/errno.h>
  42 #include <linux/err.h>
  43 #include <linux/interrupt.h>
  44 #include <linux/delay.h>
  45 #include <linux/i2c.h>
  46 #include <linux/io.h>
  47 #include <linux/sched.h>
  48 #include <linux/platform_device.h>
  49 #include <linux/clk.h>
  50
  51 #include <mach/irqs.h>
  52 #include <mach/hardware.h>
  53 #include <mach/i2c.h>
  54
  55 /** Defines ********************************************************************
  56 *******************************************************************************/
  57
  58 /* This will be the driver name the kernel reports */
  59 #define DRIVER_NAME "imx-i2c"
  60
  61 /* Default value */
  62 #define IMX_I2C_BIT_RATE        100000  /* 100kHz */
  63
  64 /* IMX I2C registers */
  65 #define IMX_I2C_IADR    0x00    /* i2c slave address */
  66 #define IMX_I2C_IFDR    0x04    /* i2c frequency divider */
  67 #define IMX_I2C_I2CR    0x08    /* i2c control */
  68 #define IMX_I2C_I2SR    0x0C    /* i2c status */
  69 #define IMX_I2C_I2DR    0x10    /* i2c transfer data */
  70
  71 /* Bits of IMX I2C registers */
  72 #define I2SR_RXAK       0x01
  73 #define I2SR_IIF        0x02
  74 #define I2SR_SRW        0x04
  75 #define I2SR_IAL        0x10
  76 #define I2SR_IBB        0x20
  77 #define I2SR_IAAS       0x40
  78 #define I2SR_ICF        0x80
  79 #define I2CR_RSTA       0x04
  80 #define I2CR_TXAK       0x08
  81 #define I2CR_MTX        0x10
  82 #define I2CR_MSTA       0x20
  83 #define I2CR_IIEN       0x40
  84 #define I2CR_IEN        0x80
  85
  86 /** Variables ******************************************************************
  87 *******************************************************************************/
  88
  89 static unsigned int disable_delay;      /* Dummy delay */
  90
  91 /*
  92  * sorted list of clock divider, register value pairs
  93  * taken from table 26-5, p.26-9, Freescale i.MX
  94  * Integrated Portable System Processor Reference Manual
  95  * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
  96  *
  97  * Duplicated divider values removed from list
  98  */
  99
 100 static u16 __initdata i2c_clk_div[50][2] = {
 101         { 22,   0x20 }, { 24,   0x21 }, { 26,   0x22 }, { 28,   0x23 },
 102         { 30,   0x00 }, { 32,   0x24 }, { 36,   0x25 }, { 40,   0x26 },
 103         { 42,   0x03 }, { 44,   0x27 }, { 48,   0x28 }, { 52,   0x05 },
 104         { 56,   0x29 }, { 60,   0x06 }, { 64,   0x2A }, { 72,   0x2B },
 105         { 80,   0x2C }, { 88,   0x09 }, { 96,   0x2D }, { 104,  0x0A },
 106         { 112,  0x2E }, { 128,  0x2F }, { 144,  0x0C }, { 160,  0x30 },
 107         { 192,  0x31 }, { 224,  0x32 }, { 240,  0x0F }, { 256,  0x33 },
 108         { 288,  0x10 }, { 320,  0x34 }, { 384,  0x35 }, { 448,  0x36 },
 109         { 480,  0x13 }, { 512,  0x37 }, { 576,  0x14 }, { 640,  0x38 },
 110         { 768,  0x39 }, { 896,  0x3A }, { 960,  0x17 }, { 1024, 0x3B },
 111         { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
 112         { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
 113         { 3072, 0x1E }, { 3840, 0x1F }
 114 };
 115
 116 struct imx_i2c_struct {
 117         struct i2c_adapter      adapter;
 118         struct resource         *res;
 119         struct clk              *clk;
 120         void __iomem            *base;
 121         int                     irq;
 122         wait_queue_head_t       queue;
 123         unsigned long           i2csr;
 124 };
 125
 126 /** Functions for IMX I2C adapter driver ***************************************
 127 *******************************************************************************/
 128
 129 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx)
 130 {
 131         unsigned long orig_jiffies = jiffies;
 132
 133         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 134
 135         /* wait for bus not busy */
 136         while (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_IBB) {
 137                 if (signal_pending(current)) {
 138                         dev_dbg(&i2c_imx->adapter.dev,
 139                                 "<%s> I2C Interrupted\n", __func__);
 140                         return -EINTR;
 141                 }
 142                 if (time_after(jiffies, orig_jiffies + HZ / 1000)) {
 143                         dev_dbg(&i2c_imx->adapter.dev,
 144                                 "<%s> I2C bus is busy\n", __func__);
 145                         return -EIO;
 146                 }
 147                 schedule();
 148         }
 149
 150         return 0;
 151 }
 152
 153 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 154 {
 155         int result;
 156
 157         result = wait_event_interruptible_timeout(i2c_imx->queue,
 158                 i2c_imx->i2csr & I2SR_IIF, HZ / 10);
 159
 160         if (unlikely(result < 0)) {
 161                 dev_dbg(&i2c_imx->adapter.dev, "<%s> result < 0\n", __func__);
 162                 return result;
 163         } else if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 164                 dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 165                 return -ETIMEDOUT;
 166         }
 167         dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
 168         i2c_imx->i2csr = 0;
 169         return 0;
 170 }
 171
 172 static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
 173 {
 174         if (readb(i2c_imx->base + IMX_I2C_I2SR) & I2SR_RXAK) {
 175                 dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
 176                 return -EIO;  /* No ACK */
 177         }
 178
 179         dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
 180         return 0;
 181 }
 182
 183 static void i2c_imx_start(struct imx_i2c_struct *i2c_imx)
 184 {
 185         unsigned int temp = 0;
 186
 187         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 188
 189         /* Enable I2C controller */
 190         writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
 191         /* Start I2C transaction */
 192         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 193         temp |= I2CR_MSTA;
 194         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 195         temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
 196         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 197 }
 198
 199 static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
 200 {
 201         unsigned int temp = 0;
 202
 203         /* Stop I2C transaction */
 204         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 205         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 206         temp &= ~I2CR_MSTA;
 207         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 208         /* setup chip registers to defaults */
 209         writeb(I2CR_IEN, i2c_imx->base + IMX_I2C_I2CR);
 210         writeb(0, i2c_imx->base + IMX_I2C_I2SR);
 211         /*
 212          * This delay caused by an i.MXL hardware bug.
 213          * If no (or too short) delay, no "STOP" bit will be generated.
 214          */
 215         udelay(disable_delay);
 216         /* Disable I2C controller */
 217         writeb(0, i2c_imx->base + IMX_I2C_I2CR);
 218 }
 219
 220 static void __init i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx,
 221                                                         unsigned int rate)
 222 {
 223         unsigned int i2c_clk_rate;
 224         unsigned int div;
 225         int i;
 226
 227         /* Divider value calculation */
 228         i2c_clk_rate = clk_get_rate(i2c_imx->clk);
 229         div = (i2c_clk_rate + rate - 1) / rate;
 230         if (div < i2c_clk_div[0][0])
 231                 i = 0;
 232         else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0])
 233                 i = ARRAY_SIZE(i2c_clk_div) - 1;
 234         else
 235                 for (i = 0; i2c_clk_div[i][0] < div; i++);
 236
 237         /* Write divider value to register */
 238         writeb(i2c_clk_div[i][1], i2c_imx->base + IMX_I2C_IFDR);
 239
 240         /*
 241          * There dummy delay is calculated.
 242          * It should be about one I2C clock period long.
 243          * This delay is used in I2C bus disable function
 244          * to fix chip hardware bug.
 245          */
 246         disable_delay = (500000U * i2c_clk_div[i][0]
 247                 + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
 248
 249         /* dev_dbg() can't be used, because adapter is not yet registered */
 250 #ifdef CONFIG_I2C_DEBUG_BUS
 251         printk(KERN_DEBUG "I2C: <%s> I2C_CLK=%d, REQ DIV=%d\n",
 252                 __func__, i2c_clk_rate, div);
 253         printk(KERN_DEBUG "I2C: <%s> IFDR[IC]=0x%x, REAL DIV=%d\n",
 254                 __func__, i2c_clk_div[i][1], i2c_clk_div[i][0]);
 255 #endif
 256 }
 257
 258 static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 259 {
 260         struct imx_i2c_struct *i2c_imx = dev_id;
 261         unsigned int temp;
 262
 263         temp = readb(i2c_imx->base + IMX_I2C_I2SR);
 264         if (temp & I2SR_IIF) {
 265                 /* save status register */
 266                 i2c_imx->i2csr = temp;
 267                 temp &= ~I2SR_IIF;
 268                 writeb(temp, i2c_imx->base + IMX_I2C_I2SR);
 269                 wake_up_interruptible(&i2c_imx->queue);
 270                 return IRQ_HANDLED;
 271         }
 272
 273         return IRQ_NONE;
 274 }
 275
 276 static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
 277 {
 278         int i, result;
 279
 280         dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
 281                 __func__, msgs->addr << 1);
 282
 283         /* write slave address */
 284         writeb(msgs->addr << 1, i2c_imx->base + IMX_I2C_I2DR);
 285         result = i2c_imx_trx_complete(i2c_imx);
 286         if (result)
 287                 return result;
 288         result = i2c_imx_acked(i2c_imx);
 289         if (result)
 290                 return result;
 291         dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
 292
 293         /* write data */
 294         for (i = 0; i < msgs->len; i++) {
 295                 dev_dbg(&i2c_imx->adapter.dev,
 296                         "<%s> write byte: B%d=0x%X\n",
 297                         __func__, i, msgs->buf[i]);
 298                 writeb(msgs->buf[i], i2c_imx->base + IMX_I2C_I2DR);
 299                 result = i2c_imx_trx_complete(i2c_imx);
 300                 if (result)
 301                         return result;
 302                 result = i2c_imx_acked(i2c_imx);
 303                 if (result)
 304                         return result;
 305         }
 306         return 0;
 307 }
 308
 309 static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
 310 {
 311         int i, result;
 312         unsigned int temp;
 313
 314         dev_dbg(&i2c_imx->adapter.dev,
 315                 "<%s> write slave address: addr=0x%x\n",
 316                 __func__, (msgs->addr << 1) | 0x01);
 317
 318         /* write slave address */
 319         writeb((msgs->addr << 1) | 0x01, i2c_imx->base + IMX_I2C_I2DR);
 320         result = i2c_imx_trx_complete(i2c_imx);
 321         if (result)
 322                 return result;
 323         result = i2c_imx_acked(i2c_imx);
 324         if (result)
 325                 return result;
 326
 327         dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
 328
 329         /* setup bus to read data */
 330         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 331         temp &= ~I2CR_MTX;
 332         if (msgs->len - 1)
 333                 temp &= ~I2CR_TXAK;
 334         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 335         readb(i2c_imx->base + IMX_I2C_I2DR); /* dummy read */
 336
 337         dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
 338
 339         /* read data */
 340         for (i = 0; i < msgs->len; i++) {
 341                 result = i2c_imx_trx_complete(i2c_imx);
 342                 if (result)
 343                         return result;
 344                 if (i == (msgs->len - 1)) {
 345                         dev_dbg(&i2c_imx->adapter.dev,
 346                                 "<%s> clear MSTA\n", __func__);
 347                         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 348                         temp &= ~I2CR_MSTA;
 349                         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 350                 } else if (i == (msgs->len - 2)) {
 351                         dev_dbg(&i2c_imx->adapter.dev,
 352                                 "<%s> set TXAK\n", __func__);
 353                         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 354                         temp |= I2CR_TXAK;
 355                         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 356                 }
 357                 msgs->buf[i] = readb(i2c_imx->base + IMX_I2C_I2DR);
 358                 dev_dbg(&i2c_imx->adapter.dev,
 359                         "<%s> read byte: B%d=0x%X\n",
 360                         __func__, i, msgs->buf[i]);
 361         }
 362         return 0;
 363 }
 364
 365 static int i2c_imx_xfer(struct i2c_adapter *adapter,
 366                                                 struct i2c_msg *msgs, int num)
 367 {
 368         unsigned int i, temp;
 369         int result;
 370         struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
 371
 372         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 373
 374         /* Check if i2c bus is not busy */
 375         result = i2c_imx_bus_busy(i2c_imx);
 376         if (result)
 377                 goto fail0;
 378
 379         /* Start I2C transfer */
 380         i2c_imx_start(i2c_imx);
 381
 382         /* read/write data */
 383         for (i = 0; i < num; i++) {
 384                 if (i) {
 385                         dev_dbg(&i2c_imx->adapter.dev,
 386                                 "<%s> repeated start\n", __func__);
 387                         temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 388                         temp |= I2CR_RSTA;
 389                         writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 390                 }
 391                 dev_dbg(&i2c_imx->adapter.dev,
 392                         "<%s> transfer message: %d\n", __func__, i);
 393                 /* write/read data */
 394 #ifdef CONFIG_I2C_DEBUG_BUS
 395                 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 396                 dev_dbg(&i2c_imx->adapter.dev, "<%s> CONTROL: IEN=%d, IIEN=%d, "
 397                         "MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__,
 398                         (temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0),
 399                         (temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0),
 400                         (temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0));
 401                 temp = readb(i2c_imx->base + IMX_I2C_I2SR);
 402                 dev_dbg(&i2c_imx->adapter.dev,
 403                         "<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, "
 404                         "IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__,
 405                         (temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0),
 406                         (temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0),
 407                         (temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),
 408                         (temp & I2SR_RXAK ? 1 : 0));
 409 #endif
 410                 if (msgs[i].flags & I2C_M_RD)
 411                         result = i2c_imx_read(i2c_imx, &msgs[i]);
 412                 else
 413                         result = i2c_imx_write(i2c_imx, &msgs[i]);
 414         }
 415
 416 fail0:
 417         /* Stop I2C transfer */
 418         i2c_imx_stop(i2c_imx);
 419
 420         dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
 421                 (result < 0) ? "error" : "success msg",
 422                         (result < 0) ? result : num);
 423         return (result < 0) ? result : num;
 424 }
 425
 426 static u32 i2c_imx_func(struct i2c_adapter *adapter)
 427 {
 428         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 429 }
 430
 431 static struct i2c_algorithm i2c_imx_algo = {
 432         .master_xfer    = i2c_imx_xfer,
 433         .functionality  = i2c_imx_func,
 434 };
 435
 436 static int __init i2c_imx_probe(struct platform_device *pdev)
 437 {
 438         struct imx_i2c_struct *i2c_imx;
 439         struct resource *res;
 440         struct imxi2c_platform_data *pdata;
 441         void __iomem *base;
 442         resource_size_t res_size;
 443         int irq;
 444         int ret;
 445
 446         dev_dbg(&pdev->dev, "<%s>\n", __func__);
 447
 448         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 449         if (!res) {
 450                 dev_err(&pdev->dev, "can't get device resources\n");
 451                 return -ENOENT;
 452         }
 453         irq = platform_get_irq(pdev, 0);
 454         if (irq < 0) {
 455                 dev_err(&pdev->dev, "can't get irq number\n");
 456                 return -ENOENT;
 457         }
 458
 459         pdata = pdev->dev.platform_data;
 460
 461         if (pdata && pdata->init) {
 462                 ret = pdata->init(&pdev->dev);
 463                 if (ret)
 464                         return ret;
 465         }
 466
 467         res_size = resource_size(res);
 468         base = ioremap(res->start, res_size);
 469         if (!base) {
 470                 dev_err(&pdev->dev, "ioremap failed\n");
 471                 ret = -EIO;
 472                 goto fail0;
 473         }
 474
 475         i2c_imx = kzalloc(sizeof(struct imx_i2c_struct), GFP_KERNEL);
 476         if (!i2c_imx) {
 477                 dev_err(&pdev->dev, "can't allocate interface\n");
 478                 ret = -ENOMEM;
 479                 goto fail1;
 480         }
 481
 482         if (!request_mem_region(res->start, res_size, DRIVER_NAME)) {
 483                 ret = -EBUSY;
 484                 goto fail2;
 485         }
 486
 487         /* Setup i2c_imx driver structure */
 488         strcpy(i2c_imx->adapter.name, pdev->name);
 489         i2c_imx->adapter.owner          = THIS_MODULE;
 490         i2c_imx->adapter.algo           = &i2c_imx_algo;
 491         i2c_imx->adapter.dev.parent     = &pdev->dev;
 492         i2c_imx->adapter.nr             = pdev->id;
 493         i2c_imx->irq                    = irq;
 494         i2c_imx->base                   = base;
 495         i2c_imx->res                    = res;
 496
 497         /* Get I2C clock */
 498         i2c_imx->clk = clk_get(&pdev->dev, "i2c_clk");
 499         if (IS_ERR(i2c_imx->clk)) {
 500                 ret = PTR_ERR(i2c_imx->clk);
 501                 dev_err(&pdev->dev, "can't get I2C clock\n");
 502                 goto fail3;
 503         }
 504         clk_enable(i2c_imx->clk);
 505
 506         /* Request IRQ */
 507         ret = request_irq(i2c_imx->irq, i2c_imx_isr, 0, pdev->name, i2c_imx);
 508         if (ret) {
 509                 dev_err(&pdev->dev, "can't claim irq %d\n", i2c_imx->irq);
 510                 goto fail4;
 511         }
 512
 513         /* Init queue */
 514         init_waitqueue_head(&i2c_imx->queue);
 515
 516         /* Set up adapter data */
 517         i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
 518
 519         /* Set up clock divider */
 520         if (pdata && pdata->bitrate)
 521                 i2c_imx_set_clk(i2c_imx, pdata->bitrate);
 522         else
 523                 i2c_imx_set_clk(i2c_imx, IMX_I2C_BIT_RATE);
 524
 525         /* Set up chip registers to defaults */
 526         writeb(0, i2c_imx->base + IMX_I2C_I2CR);
 527         writeb(0, i2c_imx->base + IMX_I2C_I2SR);
 528
 529         /* Add I2C adapter */
 530         ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
 531         if (ret < 0) {
 532                 dev_err(&pdev->dev, "registration failed\n");
 533                 goto fail5;
 534         }
 535
 536         /* Set up platform driver data */
 537         platform_set_drvdata(pdev, i2c_imx);
 538
 539         dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", i2c_imx->irq);
 540         dev_dbg(&i2c_imx->adapter.dev, "device resources from 0x%x to 0x%x\n",
 541                 i2c_imx->res->start, i2c_imx->res->end);
 542         dev_dbg(&i2c_imx->adapter.dev, "allocated %d bytes at 0x%x \n",
 543                 res_size, i2c_imx->res->start);
 544         dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
 545                 i2c_imx->adapter.name);
 546         dev_dbg(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
 547
 548         return 0;   /* Return OK */
 549
 550 fail5:
 551         free_irq(i2c_imx->irq, i2c_imx);
 552 fail4:
 553         clk_disable(i2c_imx->clk);
 554         clk_put(i2c_imx->clk);
 555 fail3:
 556         release_mem_region(i2c_imx->res->start, resource_size(res));
 557 fail2:
 558         kfree(i2c_imx);
 559 fail1:
 560         iounmap(base);
 561 fail0:
 562         if (pdata && pdata->exit)
 563                 pdata->exit(&pdev->dev);
 564         return ret; /* Return error number */
 565 }
 566
 567 static int __exit i2c_imx_remove(struct platform_device *pdev)
 568 {
 569         struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
 570         struct imxi2c_platform_data *pdata = pdev->dev.platform_data;
 571
 572         /* remove adapter */
 573         dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
 574         i2c_del_adapter(&i2c_imx->adapter);
 575         platform_set_drvdata(pdev, NULL);
 576
 577         /* free interrupt */
 578         free_irq(i2c_imx->irq, i2c_imx);
 579
 580         /* setup chip registers to defaults */
 581         writeb(0, i2c_imx->base + IMX_I2C_IADR);
 582         writeb(0, i2c_imx->base + IMX_I2C_IFDR);
 583         writeb(0, i2c_imx->base + IMX_I2C_I2CR);
 584         writeb(0, i2c_imx->base + IMX_I2C_I2SR);
 585
 586         /* Shut down hardware */
 587         if (pdata && pdata->exit)
 588                 pdata->exit(&pdev->dev);
 589
 590         /* Disable I2C clock */
 591         clk_disable(i2c_imx->clk);
 592         clk_put(i2c_imx->clk);
 593
 594         release_mem_region(i2c_imx->res->start, resource_size(i2c_imx->res));
 595         iounmap(i2c_imx->base);
 596         kfree(i2c_imx);
 597         return 0;
 598 }
 599
 600 static struct platform_driver i2c_imx_driver = {
 601         .probe          = i2c_imx_probe,
 602         .remove         = __exit_p(i2c_imx_remove),
 603         .driver = {
 604                 .name   = DRIVER_NAME,
 605                 .owner  = THIS_MODULE,
 606         }
 607 };
 608
 609 static int __init i2c_adap_imx_init(void)
 610 {
 611         return platform_driver_probe(&i2c_imx_driver, i2c_imx_probe);
 612 }
 613
 614 static void __exit i2c_adap_imx_exit(void)
 615 {
 616         platform_driver_unregister(&i2c_imx_driver);
 617 }
 618
 619 module_init(i2c_adap_imx_init);
 620 module_exit(i2c_adap_imx_exit);
 621
 622 MODULE_LICENSE("GPL");
 623 MODULE_AUTHOR("Darius Augulis");
 624 MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
 625 MODULE_ALIAS("platform:" DRIVER_NAME);